Norling, Kristoffer

Abstract [en]

Different types of models often require different tools and environments to be modeled and simulated. These tools and environments are specialized to handle specific purposes. The models created for these special purposes can then be included in the modeling and simulation of large complex systems. This scenario increases the motivation to use a co-simulation technique. Co-simulation allows for coupling of different simulators into one coherent simulation. Different parts of a system are often modeled by different departments within an enterprise or by subcontractors. Since the models often are describing enterprises’ primary know-how they become important business assets. This raises the need for a secure modeling and simulation approach. This thesis discusses different approaches regarding how to securely simulate and distribute models. We focus on a distributed co-simulation approach over wide area networks (WANs), using transmission line modeling (TLM). The approach is tested in an experimental environment at Linköping University, Sweden, and by real condition co-simulations between Sweden and Australia. A series of experiments are conducted using a simulated WAN environment and the results are put in relation to the real encrypted simulations between Sweden and Australia. We measure the performance during the simulations and evaluate the results. We observe that by distributing the co-simulation we suffer from performance losses. These losses and what parameters cause them is our primary emphasis in the evaluation. We also see that there are two types of parameters that affect the total simulation time in the distributed environment. First there are parameters that belong to the models, and then there are parameters that belong to the WAN environment. We conclude that several of the parameters have effect on the total simulation time. Especially the network delay (latency) has a significant impact.